System forclassical music

Devore Gibbon line (probably used due to budget).
Focused, accurate, produces a wide 3D soundstage with large-scale classical.

It is good to know that there are still a few people who listen to classical music. As a number of other contributors have already said, it would be a very good idea for your friends to visit a local hi-fi dealer and try a few different combinations before deciding. Also, I stongly recommend that they include an SACD player in their shopping list - Marantz make some wonderful SACD players, but a few other brands are also available. Many of the classical music labels (eg BIS, Chandos, Channel Classics, Pentatone) produce outstanding recordings on SACD and of course they cannot be copied so they must be played from the original disc. Having said that, I have found that ripping longer classical recordings (eg opera and long symphonies) often introduces unwanted clicks or gaps in the music so I find it simpler just to play all my music from the original CD.
When auditioning hifi I find it is useful to follow some sort of structure or methodology so I understand the choices I make and end up with a system that is suitable for playing the type of music that I like. These are the tests I use, but I am sure they will be able to think of some tests of their own:
1) Dynamic range. Classical music often has a wide dynamic range and many systems struggle with it. They should choose a piece of music that goes from very quiet to very loud and then back to quiet again. Do they lose detail in the loud passages? If so then it is not the right solution for them. For this test I often use Mahler's Symphony number 2 or Shostakovich's 8th symphony.
2) Piano. For some reason many systems find it difficult to produce the sound of a piano. Again this test will weed out any systems that are not upo to the job. Any piece of solo piano music will suffice
3) Human voice. Choose different types of voice - bass, counter tenor, soprano, choral and ensure that they all sound realistic. Many systems are unable to produce a warm and pleasing sound with the counter tenor and soprano voices for example.
4) Detail. Any recording on original instruments is good for this test. I find the Akademie für Alte Musik Berlin is a good choice but any recoirding on original instruments can be used. You should be able to hear all the instruments clearly and distinctly,
5) Woodwind. Again, the subtle differences between the different woodwind instruments can be hard to reproduce accurately. Listen especially for the oboe and the flute. You should be able to hear which instrument is playing and if you cannot then it would rule a system out for any discerning listener. The Brahms Serenades are a good choice for this test.
6) Your favourite piece of music. It might seem obvious but any music that is a particular favourite must sound perfect on the chosen system.
7) A poor recording. Poor recordings can sound terrible on very revealing systems. Of course we want the system to be revealing but we do want to hear the music and not just the defects.
I hope this helps.
Incidentally the composer in question is Charpentier (despite the fact that it is pronounced Charpontier).

Hegel has a lot of integrated that can be had with built-in dacs. I personally like the Schiit Ragnarok integrated and think that it could be the base for a perfect system for them. Can also be had with dac.

Then add some suitable speakers. I have heard some nice Fyne. F502 might be a good starter. Add a streamer and you have a full system for about $6k or $7k.

https://reviewary.com/fyne-audio-f502sp-review/

https://www.stereophile.com/content/schiit-audio-ragnarok-2-integrated-amplifier

They don’t sound like they are very sophisticated in audio, so I wouldn’t assume that streaming would be the source.  They may have an interest in surround sound, since they currently have in walls and these may be in some type of surround set up (as well as the SACD issue mentioned before).
   Chicago dealers: My current is Simply Stereo, located in the suburb of Palatine
I have also used Saturday Audio Exchange, located in the city on the North SIde on Belmont Ave, and Rouge Audio, on Milwaukee Ave in Bucktown.  Dave at Simply Stereo is a fantastic guy who won’t try to sell them equipment they don’t want/need and will do his utmost to try to integrate stuff that they already have, if that is the way they choose to go.  I have friends that moved into a townhome that had in walls that were of the same vintage you described and that were bizarrely wired (I couldn’t figure it out, at least).  They wanted to use their then current AVR (despite my pleas to junk it, as they could afford much better and are also discerning music listeners) and they were tremendously relieved when he didn’t bat an eyelash when he simply plugged in their AVR after making some necessary changes in their wiring (other people they dealt with were trying to sell them mega bucks systems that was a step to far for them back then.  They have since come back to Dave on their own and started upgrading).
  Finally-if they live in the area, have been vaccinated, and aren’t Serial Killers, I can host them for an afternoon.  I have one “HE” two channel system and two midfi HT systems in my home.  I use digital sources only.  Contact me privately if their is interest

Hello,
First- it’s all about the subwoofers when it comes to classical music.  The reason is to listen at lower levels you need a good sub so you don’t need a lot of volume from the integrated amp to get full dynamic range. Classical music gets very big very fast. So at higher volumes it can be a bit overwhelming. 2 Rel T5 or better for $2k, Or 2JL Audio E110 for $2k each the E112 for $2500 each gets you to 20hz, or last but not least is the KEF KF92 for $2k each that gets you to 11hz. I know two are better so you might be spending 4K. Skip the smaller KC62 due to the room size. As I said it’s all about the subs. I say buy one sub now and add the second later. 
Second- the Rogue Sphinx v2 if you don’t care about the phono for $1100 used. If you do care about the phono get the v3 for $1500 new. This thing is awesome. It has pre outs so it is ready for subs. It is tube/ class D hybrid. If you want full solid state NAD has integrated amps that have pre out for subs and you can get the BlueSound integrated or built in for $400. So $1600 will get you there or more if you want more features. I say save as much the money for the subs and speakers. You can buy the NAD 316bee for $500 but you can’t integrate the BlueSound. Probably under $1000 for amp and streaming. 
Next is a BlueSound NODE for $550 or $450 for the previous version while they last. The DACs in this thing is really good. The app is so good and easy to use. 
The speakers are really up to the listener and their room. I like KEFs R line. I would say just bookshelf speakers but then we need to add stands and those can cost a lot depending on the brand. If you stick with 7” or smaller drivers you get better imaging. Sometimes is hard for the speakers to disappear when they get too wide. I would prefer a three way but another brand that is awesome is the Revel line. Their wave guides on the tweeter almost makes room treatments unnecessary. For $2500 you can have the Revel Performa B106 bookshelf and matching stands. If you can swing it go to the M126be version with the beryllium tweeter with the latest wave guide. These were made for classical music. They will cost you an extra $2k. So $4500.
Final note- Any thing can play loud with full range of sound 20hz to 20khz. You need good gear to play softly and still get 20hz to 20khz. I have tested all of these products and theories at my house. I am fortunate that this local Hifi store In the Chicagoland area lets me try gear out in my home: 
https://holmaudio.com/
They do have all of this in the store. I own JL Audio and REL subwoofers. They also have an upgrade program to future proof your system and choices. If you are a turntable guru they had a cool TT called a working Transcriptor Skeleton on display. This thing was so cool. I hope this helped.